Centrifugal acceleration siren device



May 14, 1963 .1. DORY 3,08 58 CENTRIFUGAL ACCELERATION SIREN DEVICE Filed March 15, 1959 United States Patent Ofiice 3,089,458 Patented May 14, 1963 3,089,458 CENTRIFUGAL ACCELERATION SIREN DEVICE Jacques Dory, Villenoy par Meaux, France, assignor to Realisations Ultrasoniques, Villenoy par Meaux,

France, a corporation Filed Mar. 13, 1959, Ser. No. 799,182 Claims priority, application France Mar. 14, 1958 4 Claims. (Cl. 116-147) The present invention relates to siren devices and, more particularly, to sirens adapted to provide a powerful sonic or supersonic output.

It would be highly desirable to provide high output ultrasonic siren devices, adapted, for instance, for the precipitation of industrial fogs and smokes, and, in the case of liquid operated sirens, for ultrasonic cleaning.

It is an object of the invention to provide a high output siren arranged in such a manner that the operating fluid, at the instant of reaching the exhaust apertures, is given a considerable centrifugal acceleration.

The siren according to the invention comprises essentially a rotor member contained in a casing and provided with an axial inlet opening for receiving the operating fluid and with radially extending channels connected, at their axial end, to said opening, and running, at their peripheral end, past a plurality of apertures, or, preferably past a single aperture forming the inlet of a discharge nozzle projecting through said casing substantially tangentially to said rotary element.

The invention will be best understood from the following specification and appended drawings, in which:

FIG. 1 is a view showing diagrammatically one embodiment of the invention, partly in cross-section, and

FIG. 2 is a sectional view along axis XX of FIG. 1.

Referring to the drawings, it is seen that rotor 1 is driven in the direction of the arrow by an overhung shaft 2 actuated by motor 3.

The incoming air (or other fluid) enters the device by an axial opening 4 and is drawn into the radially extending channels 5 of the rotor, which are preferably in tangential relationship to said axial opening as shown in FIG. 2, in order to increase the accelerating effect on the air subjected to the centrifugal force. For the same reason, nozzle unit 69, as it clearly appears on the drawing, is substantially tangential to the periphery of rotor 1.

As a purely illustrative example, opening 4 has a diameter of 5 cm. and rotor 1 has a diameter of 35 cm. and comprises 30 channels 5. The motor rotates at a speed of 24,000 r.p.m., so that the frequency of the ultrasonic pressure wave transmitted by the device is 12 kc./s.

The air, accelerated in the channels of the rotor, which behaves like a centrifugal compressor, reaches in this example, a speed of about 400 m./ s. at the inlet opening 6 of the nozzle (a speed which is significant of the exceptional performance of the device).

The nozzle preferably consists of a first cylindrical section 7 followed by a frusto-conical section 8 and by a second cylindrical section 9. Preferably, the half angle of the frusto-conical section will not exceed 7. This nozzle structure, when the three sections are properly dimensioned, enables the speed of the output air pulses to be reduced to a value of 100 m./s., whereby a pressure 2 of the order of 4 kg./cm. may be attained at the outlet of the nozzle. In the above example, it has been obtained an output of 5 kw., with a power efficiency of about 25%. However much higher outputs may be obtained with sirens having similar structures.

The gap between rotor 1 and casing 10 is as small as possible and is provided with staggered joints such as 11, adapted to reduce leakages as much as possible, while not interfering with the rotation of the rotor.

It is to be understood that variations and modifications can be carried out without departing from the spirit of the invention.

What is claimed is:

l. A siren device comprising a casing and a rotor having an axial inlet chamber and an outer surface parallel to the inner surface of said casing, centrifugal flow passageways in said rotor extending in straight lines therethrough from said axial inlet chamber to a cylindrical surface portion of the rotor periphery, at least one elongated discharge nozzle projecting through said casing from an inlet opening in said cylindrical surface portion substantially tangentially thereto said cylindrical surface portion being coaxial with a corresponding cylindrical surface portion of the inner surface of the casing and the ends of said passageways being directly adjacent to said cylindrical inner surface portion, whereby the centrifugal flow from said passageways, when said rotor is rotating, will directly discharge by impulses through said inlet opening.

2. A siren device comprising a casing and a rotor having an axial inlet chamber and an outer surface parallel to the inner surface of said casing, centrifugal flow passageways in said rotor extending in straight lines therethrough from said axial inlet chamber to a cylindrical surface portion of the rotor periphery, at least one elongated discharge nozzle projecting through said casing from an inlet opening in said cylindrical surface portion substantially tangentially thereto said cylindrical surface portion being coaxial with a corresponding cylindrical surface portion of the inner surface of the casing and the ends of said passageways being directly adjacent to said cylindrical inner surface portion, and means for preventing leakage of the flow in the clearance gap between said parallel inner and outer surfaces, whereby the centrifugal flow from said passageways, when said rotor is rotating, will directly discharge by impulses through said inlet opening.

3. A siren device comprising a casing and a rotor having an axial inlet chamber and an outer surface parallel to the inner surface of said casing, centrifugal flow passageways in said rotor extending in straight lines therethrough tangentially to said axial inlet chamber, from said axial inlet chamber to a cylindrical surface portion of the rotor periphery, at least one elongated discharge nozzle projecting through said casing from an inlet opening in said cylindrical surface portion substantially tangentially thereto, said cylindrical surface portion being coaxial with a corresponding cylindrical surface portion of the inner surface of the casing and the ends of said passageways being directly adjacent to said cylindrical inner surface portion, whereby the centrifugal flow from said passageways, when said rotor is rotating, will directly discharge by impulses through said inlet opening.

4. A siren device comprising a casing and a rotor having an axial inlet chamber and an outer surface parallel to the inner surface of said casing, centrifugal flow passageways in said rotor extending in straight lines therethrough from said axial inlet chamber to a cylindrical surface portion of the rotor periphery, at least one elongated discharge nozzle projecting through said casing from an inlet opening in said cylindrical surface portion substantially tangentially thereto said cylindrical surface portion being coaxial with a corresponding cylindrical surface portion of the inner surface of the casing and the ends of said passageways being directly adjacent to said cylindrical inner surface portion, whereby the centrifugal flow from said passageways, when said rotor is rotating, will directly discharge by impulses through 4 said inlet opening, said nozzle comprising a first cylindrical section, a frustoconical section connected to said first cylindrical section and a second cylindrical section connected to said frustoconical section.

References Cited in the file of this patent UNITED STATES PATENTS 

1. A SIREN DEVICE COMPRISING A CASING AND A ROTOR HAVING AN AXIAL INLET CHAMBER AND AN OUTER SURFACE PARALLEL TO THE INNER SURFACE OF SAID CASING, CENTRIFUGAL FLOW PASSAGEWAYS IN SAID ROTOR EXTENDING IN STRAIGHT LINES THERETHROUGH FROM SAID AXIAL INLET CHAMBER TO A CYLINDRICAL SURFACE PORTION OF THE ROTOR PERIPHERY, AT LEAST ONE ELONGATED DISCHARGE NOZZLE PROJECTING THROUGH SAID CASING FROM AN INLET OPENING IN SAID CYLINDRICAL SURFACE PORTION SUBSTANTIALLY TANGENTIALLY THERETO SAID CYLINDRICAL SURFACE PORTION BEING COAXIAL WITH A CORRESPONDINGG CYLINDRICAL SURFACE PORTION OF THE INNER SURFACE OF THE CASING AND THE ENDS OF SAID PASSAGEWAYS BEING DIRECTLY ADJACENT TO SAID CYLINDRICAL INNER SURFACE PORTION, WHEREBY THE CENTRIFUGAL FLOW FROM SAID PASSAGEWAYS, WHEN SAID ROTOR IS ROTATING, WILL DIRECTLY DISCHARGE BY IMPULSES THROUGH SAID INLET OPENING. 